1. Field of the Invention
This invention relates to a centrifuge and to a method of operating same.
2. Brief Description of the Prior Art
Centrifuges are employed to separate a mixture comprising solids suspended in a liquid in order to clean the liquid. In operation, the liquid rotates with a rotor of such centrifuges and denser solids collect on the inner peripheral wall of the spinning rotor. The efficiency of operation of the centrifuge depends upon the liquid attaining a sufficiently high angular velocity, which requires the centrifuging rotor to be rotated at high speed. Since the rotary motion is wholly or mainly transmitted through the liquid by its own viscosity, the liquid is only gradually speeded up and, as it enters the rotor, its rate of flow through the rotor may have to be limited to ensure it attains sufficient angular velocity for efficient separation of the solid material from it by the centrifuging action.
Known centrifuges are normally arranged to operate with a continuous flow of liquid through the bowl or rotor, but the collected solids must usually be removed manually. This has many disadvantages, not least the fact that the apparatus is put out of use for considerable periods unless a system of replacement rotors is employed. Mechanisms have therefore been proposed for the automatic removal of the solids. In these mechanisms a member is inserted into the bowl to scrape or suck the accumulated deposits from its peripheral wall. Such mechanisms are vulnerable to damage and can add considerably to the complexity of the design; if they are permanently located within the centrifuge bowl they can disturb the liquid flow there and reduce the efficiency of separation.